Waste gas collecting device of converter

ABSTRACT

1. A WASTE GAS COLLECTING DEVICE OF A CONVERTER, COMPRISING AN APRON ARRANGED TO COVER THE ENTIRE SHELL OF THE CONVERTER EXCEPT FOR THE MOUTH OF SAID CONVERTER, OPPOSED UPRIGHT WINDSHIELD PLATES PROVIDED ON THE FRONT SIDE OF THE CONVERTER TO SHIELD BOTH SIDES OF THE CONVERTER AND APRON, A WINDSHIELD PLATE SUSPENDED BELOW THE CONVERTER, A WASTE GAS HOOD ARRANGED ABOVE THE REAR PORTION OF THE CONVERTER AND EXTENDING FORWARDLY TO A POINT TO COVER THE MOUTH OF THE CONVERTER DURING THE REACTION STAGE, SAID WASTE GAS HOOD BEING PROVIDED WITH AN OPENING AT THE FORWARD END PORTION THEREOF, AND A MOVABLE HOOD SLIDINGLY MOVED ON SAID WASTE GAS HOOD TO OPEN AND CLOSE SAID OPENING AND ADAPTED TO COVER THE MOUTH OF THE CONVERTER OVER THE SECTION OF THE ARCUATE LOCUS OF MOVEMENT OF THE CONVERTER MOUTH FROM THE POSITION IN THE REACTION STAGE TO THE POSITION IN THE MATERIAL CHARGING STAGE, SAID DEVICE   BEING USED IN A WASTE GAS TREATMENT SYSTEM HAVING A WASTE GAS EXHAUST ROUTE INCLUDING THE WASTE GAS HOOD, A DUST CHAMBER A WASTE HEAT BOILER AND A COTTRELL PRECIPITATOR, AND A SULFURIC ACID PLANT IN WHICH A WASTE GAS EMERGING FROM THE CONVERTER DURING THE REACTION STAGE AND SUPPLIED THERETO THROUGH SAID WASTE GAS EXHAUST ROUTE BY AN EXHAUST FAN IS DESULFURIZED THROUGH A PROCESS OF RECOVERING SO2 FROM SAID WASTE GAS IN THE FORM OF SULFURIC ACID.

United States Patent 1 Maeda et al.

[ WASTE GAS COLLECTING DEVICE OF CONVERTER [76] Inventors: l-lidenori Maeda, Tokyo; Yujiro Matsui, Yokohama; Tsukasa lkeda, Kosakamachi; Eikichi Mohri, Tokyo, all of Japan [73] Assignee: Taisei Kensetsu Kabushiki Kaisha,

Dowa Kogyo Kabushiki Kaisha, Tokyo,.lapan [22] Filed: Feb. 20, 1973 [21] Appl. No.: 333,506 [30] Foreign Application Priority Data Mar. 29, 1972 Japan 47/30752 [52] US. Cl. 266/18, 266/35 [51] Int. Cl. C210 5/38 [58] Field of Search 266/15-19, 266/35, 36 R; 75/72-76 [56] References Cited UNITED STATES PATENTS l,4l7,538 5/l922 McGregor 266/8 2,768,062 l0/l956 Kartenbeck 75/75 [111 3,848,860 [451 Nov. 19, 1974 [57] ABSTRACT A astegis collecting device of a converter, comprising an apron arranged to cover the entire shell of the converter except for the mouth of said converter, opposed upright windshield plates provided on the front side of the converter to shield both sides of the converter and apron, a windshield plate suspended below the converter, a waste gas hood arranged above the rear portion of the converter and extending forwardly to a point to cover the mouth of the converter during the reaction stage, said waste gas hood being provided with an opening at the forward end portion thereof, and a movable hood slidingly moved on said waste gas hood to open and close said opening and adapted to cover the mouth of the converter over the section of the arcuate locus of movement of the converter mouth from the position in the reaction stage to the position in the material charging stage, said device being used in a waste gas treatment system having a waste gas exhaust route including the waste gas hood, a dust chamber, a waste heat boiler and a Cottrell precipitator, and a sulfuric acid plant in which a waste gas emerging from the converter during the reaction state and supplied thereto through said waste gas exhaust route by an exhaust fan is desulfurized through a process of recovering S0 from said waste gas in the form of sulfuric acid.

I Claim, 4 Drawing Figures PATENTS, 55V 1 9 I974 SHEET 10F 3 FIG.

PATENTEL 1 91974 3.848.860

SHEEF 30F 3 FIG. 4

WASTE GAS COLLECTING DEVICE OF CONVERTER BACKGROUND OF THE INVENTION l. Field of the Invention:

This invention relates to a waste gas collecting device of a converter.

2. Description of the Prior Art:

In the operation, for example, of a copper converter, the converter is turned forwardly and backwardly for charging materials, slag summing and pouring. It has been considered extremely difficult in the operation of conventional converters to collect the SO -containing waste gas which spouts with sparks from the mouth of the converter when the mouth is exposed outwardly of a waste gas hood during turning of the converter.

I-Ieretofore, a waste gas collecting device of this type of converter is disposed within a waste gas hood so as to collect the waste gas which emerges only in the process of reaction from the mouth of the converter. The reaction of a bath in the converter is carried out with air blown thereinto from the tuyere of the converter, and the gas generated in the converter and spouting from the mouth is sucked by an exhaust fan through the waste gas hood, a dust chamber, a waste heat boiler of the converter and a Cottrell and led to a sulfuric acid plant wherein S contained in the gas is recovered as sulfuric acid, and the resultant substantially non-toxic gas is released into the atmosphere. With such a waste gas collecting device, it has been extremely difficult to collect the waste gas emerging from the mouth when the mouth is exposed outwardly of the waste gas hood during operation of the converter other than the reaction, with the result that the working environment has been spoiled or an air pollution problem has been induced.

Nevertheless, the only countermeasure which is taken at the present time is to provide an additional exhaust route separately from the conventional exhaust route and exhaust the waste gas through said additional exhaust route. This is because the provision of a complete waste gas collecting device and waste gas purifying device will add to the facility cost, with no prospect of successful collection of S0 and hence is a great economical disadvantage.

SUMMARY OF THE INVENTION The present invention has been achieved with a view to eliminating such disadvantage, and proposes a waste gas collecting device of a converter, which comprises an apron arranged to cover the entire shell of the converter except for the mouth of said converter, opposed upright windshield plates provided on the front side of the converter to shield both sides of the converter and apron, a windshield plate suspended below the converter, a waste gas hood arranged above the rear portion of the converter and extending forwardly to a point to cover the mouth of the converter during the reaction stage, said waste gas hood being provided with an opening at the forward end portion thereof, and a movable hood slidingly moved on said waste gas hood to open and close said opening and adapted to cover the mouth of the converter over the section of the arcuate locus of movement of the converter mouth from the position in the reaction stage to the position in the material charging stage, and which is adapted for use in a waste gas treatment system in which a waste gas is sucked by an exhaust fan through a waste gas exhaust route including the waste gas hood, a dust chamber, a waste heat boiler and a Cottrell precipitator, and led to a sulfuric acid plant wherein S0 contained in said waste gas is recovered as sulfuric acid.

In the device of the invention, the mouth of the converter is covered, in the section of the locus of movement of said mouth from the position in the reaction stage to the position in the material charging stage, by the movable hood which opens or closes the opening of the waste gas hood incident to the rotation of the converter in one or the other direction, as stated above. Therefore, in no case will the waste gas be allowed to leak to the outside of the waste gas hood during rotation of the converter. On the other hand, the intrusion of free air into the exhaust route from the waste gas hood can be prevented by the apron which is arranged concentrically with the shell of the converter in a manner to cover said shell except for the mouth.

During the slag scumming and pouring stages of the converter, the opening of the waste gas hood is halfopened by the movable hood, whereby the waste gas spouting from the mouth is sucked into the waste gas hood through the half-opened opening. In this case, the waste gas flow is not disturbed by the outside air flows as both sides of the converter and apron are shielded by the opposed upright windshield plates provided on the front side of the converter and the underside of the converter by the windshield plate suspended below the converter, so that the sucking effect of the waste gas hood is enhanced and the waste gas is led into the conventional exhaust route from said waste gas hood. Since no waste gas is allowed to expand in the working area, the environmental air is maintained clean, ensuring the safety of working and the problem of air pollution can be eliminated.

The device of the invention is advantageous in that the waste gas can be collected substantially completely even during the material charging, slag scumming and pouring stages, in that the operation is simple, in that the operational cost is essentially the same as when the conventional exhaust route is used, and in that it can be materialized by the addition to a conventional device members necessary for the collection of waste gas which are very inexpensive, can be produced simply in a short period of time and involves substantially no members which call for maintenance and inspection.

It is also to be noted that, with the device of the invention, the exhaust route is used fully during the reaction stage, without increasing the capacity of the exhaust fan, so that it is unnecessary to provide newly additional devices, such as a waste gas collecting device, a cleaning device and an exhaust fan. Further, since the exhaust route used during the reaction stage is used during the other stages, S0 gas contained in the waste gas is completely recovered in the form of sulfuric acid at the sulfuric acid plant and hence the occurrence of air pollution can be precluded. The device of the invention enables also the heat of the waste gas to be recovered and, therefore, is advantageously used in many production lines as a member thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2 and 3 are a vertical sectional view, a front elevational view and a plan view respectively of an embodiment of the present invention; and

FIG. 4 is an illustrative diagram of a waste gas exhaust system.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will be described by way of example hereunder with reference to the drawings. In the drawings, reference numeral 1 designates a copper converter, 2 a material charging mouth of the converter which serves simultaneously as a waste gas exhaust port, and 3 a tuyere of the converter through which air is introduced. An apron 4 is provided concentrially, covering the entire outer surface of the converter 1, except for the mouth 2.

Reference characters A, B, C and D respectively indicate the positions of the mouth 2 of the converter 1 in the reaction stage, material charging stage, slag scumming stage and pouring stage.

A waste gas hood 5 is provided above the converter 1 and secured in position by beams (not shown). This waste gas hood 5 is composed of opposite side plates 6 and a top cover plate 7 fixed to the top ends of said side plates. The top cover plate 7 covers only the position A which the mouth 2 takes in the reaction stage and has an opening 8 at the front end portion thereof. In the material charging stage, the mouth 2 of the converter 1 is positioned below the opening 8 and materials are charged into the converter 1 through said opening 8 and mouth 2.

Guide rails 9 are provided extending along the top ends of the side plates 6, at the opening 8, of the waste gas hood 5 and further extending from the rear end of said opening to above the top cover plate 7 of said hood. A streamlined movable hood 10 is slidably mounted on the guide rails 9. This movable hood 10 is provided thereon with fixed studs 11 and cables 12 are respectively anchored to said studs 11 at one ends thereof, with the other ends connected to winding means 13. The arrangement is made such that, when the cables 12 are wound on or unwound fromthe winding means 13, the movable hood 10 slidingly moves on the guide rails 9, opening or closing the opening 8 of the waste gas hood 5. Reference characters a, b and c respectively indicatethe positions of the movable hood 10, in which the opening 8 of the waste gas hood 5 is fully closed, half-opened and fully opened by said movable hood. Reference numeral 14 designates a cleaning opening provided in the waste gas hood 5.

On the front side of the converter 1 are provided opposed upright windshield plates 15 which are erected on the floor and seal the from half portion of the outer surface of the converter 1 and the opposite side edges of the apron 4.

Reference numeral 16 designates rollers for rotating the converter 1. At the bottom of the converter 1 is provided a windshield plate 17 which is extending downwardly from a pivot shaft 18 connected to the apron 4 and serves, together with the aforesaid upright windshield plates 18, to prevent the waste gas from being disturbed by outside air flows, during the slag scumming and pouring stages. Reference numeral 19 designates a ladle pit and 20 designates a ladle.

In FIG. 4, there is shown schematically a waste gas exhaust system which will be provided successive to the waste gas hood of the device of this invention, and which comprises a blower 21 for introducing air into the converter, a conduit 22 extending from said blower 21 to the tuyere 3 of the converter, a dust chamber 23 into which the waste gas sucked into the waste gas hood is led, a waste heat boilder 24, a Cottrell precipitator 25, a waste gas exhaust duct 26, a waste gas exhaust fan 27, a sulfuric acid plant 28 for recovering 50-, in the waste gas in the form of sulfuric acid, and an exhaust conduit 29 for releasing the desulfurized waste gas into the atmosphere therethrough. This waste gas exhaust system is conventionally known and will not be described in further detail herein.

The waste gas collecting device of the invention constructed as described above is operated in the following manner: Namely, in the reaction stage of the converter 1, or when the mouth 2 of the converter 1 is located in the position-A, the movable hood 10 is shifted to the position a by the operation of the winding means 13, to close fully the opening 8 at the front end portion of the top cover plate of the waste gas hood 5. In this case, the tuyere 3 is located within a bath in the converter, and air is blown into the bath with a full load through said tuyere. The reaction gas formed within the converter and spouting from the mouth 2 is exhausted by the above-described waste gas exhaust system through the waste gas hood 5, by the exhaust fan operating at a full load. In this case, no waste gas is allowed to leak to the outside as the mouth 2 is completely covered by the waste gas hood 5 and movable hood 10.

Upon completion of the reaction, the converter 1 is turned forwardly and its mouth 2 is shifted from the position A to B or from the position in the reaction stage to the position in the material charging stage. In the past, the mouth 2 has been exposed to the outside of the waste gas hood during turning of the converter. With the device of the invention, however, the movable hood 10 is still in the position a, or the mouth 2 is still completely enclosed by the waste gas hood 5 and movable hood 10, during this period, so that the waste gas spouting from the mouth 2 is not allowed to leak to the outside. The amount of air introduced into the converter is gradually reduced, incident to the forward turn of the converter and finally become zero when the converter takes the material charging position. However, there is some time lag before the spouting of waste gas terminates, due to the residual pressure in the converter. The exhaust fan is operating still at its full load at this time.

Now, when the mouth 2 of the converter 1 has been set in the position B or the position in the material charging stage, and the spouting of waste gas has terminated, the cables 12 are wound up by the winding means 13 to shift the movable hood 10 along the guide rails 7 to the position 0. In this position of the movable hood 10, the opening 8 is fully opened, providing for charging of materials into the converter through said opening 8 and mouth 2. During the material charging stage, the waste gas is sucked and collected substantially entirely into the waste gas hood 5, and the waste gas collecting effect of the hood is promoted by the apron 4 and the side plates 6 of the waste gas hood 5 successive to said apron, which block the outside air tending to be sucked into the hood. In this case, the tuyere 3 of the converter is located outside of the bath and no air is introduced into the converter therefrom, but the exhaust fan is operated at its full load.

When the mouth 2 of the converter 1 has been set in the position C or the position in the slag scumming stage, the movable hood 10 is shifted to the position b in which the opening 8 is half-opened, and the waste gas emerging from the converter during the period of scumming the slug into the ladle 20 is sucked and collected substantially entirely into the waste gas hood 5 through the half-opened opening 8. In this case, the waste gas collecting effect is enhanced by the apron 4, the opposite upright side plates 6 of the waste gas hood 5, the opposed upright windshield plates on the front side of the converter and the windshield plate 17 below the converter, all of which block the outside air tending to be sucked into the hood and thereby prevent the waste gas flow from being disturbed by such outside air flows. During the slag scumming stage, the tuyere 3 is located outside of the bath and no air is introduced therefrom. The exhaust fan is operated at its full load.

Then, the mouth 2 of the converter 1 is shifted to the position D, that is, the position in the pouring stage, and the molten bath is poured into the ladle 20 from the converter. The waste gas emerging from the converter in this case is substantially entirely sucked and collected into the waste gas hood through the halfopened opening 8, similar to the slag scumming stage.

When it is desired to set the converter 1 in the reaction position A from any other position, i.e. any one of the positions in which the mouth 2 is located in the positions B, C and D, by turning said converter, the converter is once stopped at the position B. of the mouth 2 during turning from said other position, and the movable hood 10 is shifted to its full opening position a so that a projection of the mouth 2 will not abut against the forward edge of said movable hood. Thereafter, the converter is turned slowly to the position A and air is introduced into the bath in the converter 1 from the tuyere 3 at the maximum rate. The waste gas spouting from the mouth 2 during this period is completely sucked into and exhausted through the waste gas route, without being allowed to leak to the outside of the converter.

With the device of the invention, as may be understood from the description herein, the waste gas is led to the sulfuric acid plant through the waste gas route without being allowed to leak to the outside, throughout the operation of the converter and, after desulfurized in the sulfuric acid plant, released into the atmosphere.

Although the present invention has been described and illustrated herein in terms of a specific embodiment thereof, it should be understood that the invention is not restricted only to the embodiment but many changes and modifications are possible within the scope not deviating from the spirit of the invention.

What is claimed is:

1. A waste gas collecting device of a converter, comprising an apron arranged to cover the entire shell of the converter except for the mouth of said converter, opposed upright windshield plates provided on the front side of the converter to shield both sides of the converter and apron, a windshield plate suspended below the converter, a waste gas hood arranged above the rear portion of the converter and extending forwardly to a point to cover the mouth of the converter during the reaction stage, said waste gas hood being provided with an opening at the forward end portion thereof, and a movable hood slidingly moved on said waste gas hood to open and close said opening and adapted to cover the mouth of the converter over the section of the arcuate locus of movement of the converter mouth from the position in the reaction stage to the position in the material charging stage, said device being used in a waste gas treatment system having a waste gas exhaust route including the waste gas hood, a dust chamber, a waste heat boiler and a Cottrell precipitator, and a sulfuric acid plant in which a waste gas emerging from the converter during the reaction stage and supplied thereto through said waste gas exhaust route by an exhaust fan is desulfurized through a process of recovering S0 from said waste gas in the form of sulfuric acid. 

